What was found
EWR- FLIGHT 4161, THE CREW NOTED THAT THE LANDING GEAR DISAGREEMENT LIGHT ILLUMINATED FOR THE RIGHT MAIN GEAR. THE CREW RETURNED TO EWR WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE RIGHT MAIN GEAR UPLOCK BOX, PERFORMED A OPERATIONAL CHECK OF THE LANDING GEAR SYSTEM, NO DEFECTS NOTED. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.